1. Field of the Invention
The present invention relates generally to a touch screen device, and more particularly, to an apparatus and method for browsing of a map displayed on a touch screen.
2. Description of the Related Art
As portable terminals, e.g., a cellular phone, a Personal Communication System (PCS), a Personal Digital Assistant (PDA), an International Mobile Telecommunication-2000 (IMT-2000) terminal, a laptop computer, a tablet Personal Computer (PC), etc., are commonly used, service providers and terminal manufacturers often provide additional functions to increase utilization of these portable terminals. A map service provided by the portable terminal is an example of an additional function.
Often, the map service is provided by a portable terminal including a touch screen display, in such a manner that a user drags a specific point on the map to shift a displayed portion of the map.
Additionally, this type of browsing mechanism, based on dragging a point on a touch screen, is not only applicable to portable terminals, but also to other devices having a touch screen. For example, a large, fixed touch screen sign may be installed in a subway station, a downtown area, etc., which provides a map service with browsing capabilities as described above.
Specifically, browsing the displayed map is based on an interaction between a device and a user. That is, the device analyzes a user input to control a displayed portion of the map shown on a screen. As described above, a typical browsing mechanism shifts a displayed portion of the map by dragging, and also enlarges/shrinks the displayed portion, e.g., depending on a distance between a plurality of touch inputs. Herein, when shifting the displayed portion, all points on the screen are shifted equally by Δx in a horizontal direction and by Δy in a vertical direction. Because a position initially recognized by the user is often shifted outside the screen when shifting the displayed portion, the user loses recognized positions. Consequently, it becomes difficult for the user to recognize a previous browsing position, and thus, when intending to return to the previous browsing position, the user may not know a proper shift direction or may have to repeat the screen shift in an opposition direction.
As described above, when browsing the map, it is often difficult for a user to recognize a relative positional relationship between points recognized by the user, after shifting an originally displayed portion of the map.